MobileAppProgramming/LatLngToXY.java at master · kimchioverfit/MobileAppProgramming · GitHub

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package com.example.weatherwidget.view.clock;

import android.util.Log;

/***
 * It's open sourse
 * Reference by https://gist.github.com/fronteer-kr/14d7f779d52a21ac2f16
 *기능은 GPS 에서 얻을 세계 좌표가 한국 지도 좌표로 변견한다
 */
public class LatLngToXY {
    public static int TO_GRID = 0;
    public static int TO_GPS = 1;
    public  static LatXLngY tmp;
    public  void method(double x , double y) {
         tmp = convertGRID_GPS(TO_GRID, x, y);
        Log.i(">>", "x = " + tmp.x + ", y = " + tmp.y);

    }


    public  LatXLngY convertGRID_GPS(int mode, double lat_X, double lng_Y )
    {
        double RE = 6371.00877; // 지구 반경(km)
        double GRID = 5.0; // 격자 간격(km)
        double SLAT1 = 30.0; // 투영 위도1(degree)
        double SLAT2 = 60.0; // 투영 위도2(degree)
        double OLON = 126.0; // 기준점 경도(degree)
        double OLAT = 38.0; // 기준점 위도(degree)
        double XO = 43; // 기준점 X좌표(GRID)
        double YO = 136; // 기1준점 Y좌표(GRID)

        //
        // LCC DFS 좌표변환 ( code : "TO_GRID"(위경도->좌표, lat_X:위도,  lng_Y:경도), "TO_GPS"(좌표->위경도,  lat_X:x, lng_Y:y) )
        //


        double DEGRAD = Math.PI / 180.0;
        double RADDEG = 180.0 / Math.PI;

        double re = RE / GRID;
        double slat1 = SLAT1 * DEGRAD;
        double slat2 = SLAT2 * DEGRAD;
        double olon = OLON * DEGRAD;
        double olat = OLAT * DEGRAD;

        double sn = Math.tan(Math.PI * 0.25 + slat2 * 0.5) / Math.tan(Math.PI * 0.25 + slat1 * 0.5);
        sn = Math.log(Math.cos(slat1) / Math.cos(slat2)) / Math.log(sn);
        double sf = Math.tan(Math.PI * 0.25 + slat1 * 0.5);
        sf = Math.pow(sf, sn) * Math.cos(slat1) / sn;
        double ro = Math.tan(Math.PI * 0.25 + olat * 0.5);
        ro = re * sf / Math.pow(ro, sn);
        LatXLngY rs = new LatXLngY();

        if (mode == TO_GRID) {
            rs.lat = lat_X;
            rs.lng = lng_Y;
            double ra = Math.tan(Math.PI * 0.25 + (lat_X) * DEGRAD * 0.5);
            ra = re * sf / Math.pow(ra, sn);
            double theta = lng_Y * DEGRAD - olon;
            if (theta > Math.PI) theta -= 2.0 * Math.PI;
            if (theta < -Math.PI) theta += 2.0 * Math.PI;
            theta *= sn;
            rs.x = Math.floor(ra * Math.sin(theta) + XO + 0.5);
            rs.y = Math.floor(ro - ra * Math.cos(theta) + YO + 0.5);
        }
        else {
            rs.x = lat_X;
            rs.y = lng_Y;
            double xn = lat_X - XO;
            double yn = ro - lng_Y + YO;
            double ra = Math.sqrt(xn * xn + yn * yn);
            if (sn < 0.0) {
                ra = -ra;
            }
            double alat = Math.pow((re * sf / ra), (1.0 / sn));
            alat = 2.0 * Math.atan(alat) - Math.PI * 0.5;

            double theta = 0.0;
            if (Math.abs(xn) <= 0.0) {
                theta = 0.0;
            }
            else {
                if (Math.abs(yn) <= 0.0) {
                    theta = Math.PI * 0.5;
                    if (xn < 0.0) {
                        theta = -theta;
                    }
                }
                else theta = Math.atan2(xn, yn);
            }
            double alon = theta / sn + olon;
            rs.lat = alat * RADDEG;
            rs.lng = alon * RADDEG;
        }
        return rs;
    }


    class LatXLngY
    {
        public double lat;
        public double lng;

        public double x;
        public double y;

    }
}